The present invention relates to a process for a making knitted tights or panty-hose composed of two halves which are joined by a seam passing from the belt to the crutch and which also comprises an elastic belt incorporated therein.
Incorporated elastic belt refers here to a belt knitted at the same time as the tights themselves, by opposition to the frequently employed method consisting in sewing a separate elastic tape to the top edge of the tights.
In tights where the belt is made in one piece by circular knitting, said belt may be easily rendered elastic by using an elastic yarn added to the basic yarn.
The situation is quite different when the tights are composed of two pieces which are joined by a seam from the front top edge of the belt to the rear top edge, via the crutch. In this case, two hose elements are knitted separately, each having the total length of the tights and each representing a leg plus the height of the panty up to the top edge of the belt. These two hose elements are advantageously obtained by using a circular knitting machine. Each is then slit along a generatrix from the top edge over the desired height of the panty. The corresponding edges of the two slits are joined and sewn together respectively to obtain a pair of tights with a seam.
If an elastic yarn is incorporated in the top part of each of the two hose elements, it slips and ladders when said hose elements are slit has just been explained.
Two solutions have been proposed up to the present time to remedy this situation. In published German Application No. 1 785 346, it is envisaged to knit an elastic yarn with a basic yarn over the whole perimeter of the belt, alternately one wale out of two. In practice, the elasticity of a belt made in this way is observed to be insufficient. French Patent No. 70-00922 (2 076 342) envisages knitting the elastic yarn with the basic yarn in a zone of width limited to a few wales which are all immediately adjacent one another. When each hose element is then slit, the line of cut is not always well centred the edges are not neat and it happened that the elastic yarn slips.
It is a principal object of the invention to provide another solution which differs from the solutions described in these patents and which is advantageous from the standpoint of slitting the hose elements and anchoring the elastic yarn.
In the present case, a double-cylinder double feed half-hose knitting machine is used, of the type comprising a conventional welt bolt cam and a Jacquard system.
Each half-hose is knitted in tubular form, beginning at the top welt, using the basic yarn chosen (made of synthetic or natural material or a blend) and, in addition to the basic yarn, an elastic yarn is used which is introduced for example in each course of stitches over a height depending on the size of the finished article. In a vertical strip with a width of about 2 cm which concerns a number of needles between 12 and 24, the elastic yarn is knitted alone with the needles of the bottom cylinder except the central needle of this strip which is left in rest position, and only over the chosen width, the other needles of the bottom cylinder being left in rest position, and all the needles of the top cylinder also being left in rest position.
At the following feed, the basic yarn alone is used as usual, with all the needles of the two cylinders.
This operation is continued in this way alternately over the whole height of the elastic belt and after having made said belt, normal knitting is effected up to the tip using the basic yarn on the two feeds, i.e. at each yarn distribution.
The two hose elements thus being produced, each may be cut to form a slit over a height which corresponds to that of the panty, by cutting the yarns at the centre of the vertical strip, corresponding to the location of the central needle left in rest position when the elastic yarn was being knitted. The latter is blocked by the manner in which it was knitted and it does not run. The two hose elements are then sewn together by a flat or overcast seam along the two edges of the slits, and the desired tights are obtained.
The invention also relates to any tights or pantyhose made according to the above method; such tights are recognized from the vertical strip which extends on either side of the flat seam over the height of the elastic belt incorporated therein. The appearance of this strip necessarily differs from the appearance of the adjacent and lower parts of the tights.
On these tights, before the slit is cut and the seam is made, in a strip a few centimeters wide, and over the height of the elastic belt, the elastic yarn is knitted partially, one wale out of two, with the exception of the central wale where the yarn is floated. On the finished tights, the seam is at the centre of this strip, where the central wale was located.